2. Click the Upgrade your Account link.
3. Click the Upgrade Now button.
4. Choose to upgrade to a Business account and follow
instructions to complete the upgrade.
5. If you haven't already, add a bank account to become a
Verified member. Follow the instructions on the PayPal site.
This process may take 2-3 business days.

For customers who wish to use their existing
merchant bank account with the PayPal PayFlow gateway can sign
up for
a PayPal PayFlow account here

a. On your Web Shop or external web site create a $0.01 or £0.01 product and press Buy b. On the Shopping Basket screen press Checkout

c. Enter test details for New Customer and press Create Login d. Enter test Delivery Address press Add e. Press Set this as Billing Address, press Ship To This Address f. Under "Pay by Credit/Debit Card" select option and press Proceed To Payments button g. You will now be redirected to the PayPal login / credit card payment page. You may complete a checkout - but note real money will be exchanged.

Test complete.

Allow Customers to Checkout Without Creating a PayPal Account (optional)

To turn the feature on or off, simply log in to PayPal, go to Profile,
click ‘Website Payment Preferences’ under the Selling Preferences
column and tick the yes/no box under PayPal Account Optional.

More details here:https://www.paypal.com/uk/cgi-bin/webscr?cmd=xpt/cps/general/OptionalAccount-outside

How do I integrate Express Checkout?

Add Express Checkout in a few easy steps

To use Express Checkout you will need to create API Credentials. (not API Certificate).